Anode tube for ionic valves for highvoltage static current converters



May 3, 1949. G. J. PERSSON 2,468,836

ANODE TUBE FOR IONIC VALVES FOR HIGH-VOLTAGE STATIC CURRENT CONVERTERS Filed Nov. 29, 1945 Patented May 3, 1949 AN ODE TUBE FOR IONIC VALVES FOR HIGH- VOLTAGE STATIC CURRENT CONVERTERS Gunnar J. Persson, Ludvika, Sweden, assignor to Elektriska Aktiebolaget, Vasteras, Sweden, a corporation of Sweden Application November 29, 1945, Serial No. 631,678 In Sweden July 10, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires July 10, 1964 Allmanna Svenska 4 Claims.

The United States Patent 2,446,600 of Uno Lamm describes an anode tube for ionic valves for high voltage static current converters having a number of conducting bodies adjacent to the current path and serving to equalize the voltage during the impermeable periods, said conducting bodies being so dimensioned as to fill out a certain portion of the volume inside the anode tube between the anode and the cathode space. In the specification of the said patent application, this condition has been defined more precisely so, that it refers to the external dimensions of the bodies but does not exclude the provision of cavities in the bodies which in electrostatic respectcan be regarded as entirely closed, i. e. that no electric fields producing or maintaining an ionisation can be formed therein. Such cavities are then regarded as integrating parts of the bodies.

It has now been found, that it is often advisable to construct such hollow voltage equalizing bodies, whether they satisfy the dimensioning rule given in Patent 2,446,600 or not, of sheet metal, preferably sheet iron, in such manner that their cavities, except the channels for conducting the current, will be comparatively free from electric fields and from discharges. It is generally easier to produce sheet iron than solid iron bodies of the high degree of purity which is necessary in static current converter vessels. It may also be advantageous that the volume of the inner cavities is comparatively large, especially if the bodies are so constructed that these cavities communicate directly with the through channels for the arcs. Hereby the cavities will serve, at the alternative expansion of the vapor columns in the arc channels during the operating periods and contraction of the said columns during the impermeable periods, as a kind of equalizing receptacles and thus reduce the speed of the longitudinal movements of the vapor, whereby an equal distribution of the electric field along the conductive bodies is facilitated. Finally, the manufacturing of the bodies pressed from sheet metal is as a rule easier than that of solid bodies which need turning. An anode tube having conducting bodies of the aforesaid type forms the object of the present invention.

A form of the invention is illustrated in the accompanying drawing which shows a portion of an anode tube with conducting bodies therein equalizing. Each such body preferably consists of two parts of sheet metal, pressed into a suitable dish shape and welded together at the periphery end enclosing a hollow space which communicates with each arc channel 4 (several such channels being arranged on the periphery of a circle) by an annular slot 3 but is otherwise preferably closed so that no electric field. can be formed therein, as its walls have the same potential everywhere. Small openings, if any, do not disturb this condition. It is also possible, instead of welding the two parts together, to insulate them from each other and to leave therebetween a small voltage difference insuificient for producing a disturbing electric field. Through the annular slots 3, the aforesaid equalizing of pressure variations in the arc channels 4 may take place.

For securing pins 5 intended to hold the bodies in the enclosing tube in a manner described in Patent 2,446,600, graphite rings 6 may for instance be introduced into the bodies at the periphery thereof. It is of course also possible to secure the pins 5 in some suitable sheet metal structure. The leads 1 serving to keep the bodies 2 at an appropriate potential may be screwed directly to the sheet metal in the manner illustrated and may be terminated in a vacuum-tight manner outside the tube l in a way previously described.

At the top of the tube I, there is shown an anode 8 which has, opposite the circular row of arc channels, an annular groove 9. The purpose of this shaping of the anode is to establish a communication between the parallel channels, in which an arc-back current, if arising, shall have the possibility of developing freely, as it may otherwise cause over-voltages which may be more dangerous than the arc-back itself. The same result may be gained by placing the anode at a larger distance from the first conducting body than the mutual distance between the rest of said bodies.

I claim as my invention:

1. An anode tube for ionic valves for high volt- 2. An anode tube according to claim 1 in which said empty spaces of the bodies are in direct communication with said channels for the passage of the current.

3. An anode tube-according to claim 1 in which graphite rings are inserted in said bodies at the periphery thereof, and holding members for said bodies secured in said graphite rings.

4. An anode tube according to claim 1 having a plurality of parallel current carrying channels, and in which a communication permitting a flow of current is established between said channels at the anode end of the tube.

GUNNAR J. PERSSON.

4 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,251,923 Druyvesteyn Aug. 12, 1941 2,301,980 Steenbeck Nov. 17, 1942 FOREIGN PATENTS Number Country Date 442,092 Great Britain Feb. 3, 1936 442,414 Great Britain Feb. 7, 1936 459,863 Great Britain Jan. 15, 1937 469,246 Germany June 14, 1921 555,509 Great Britain Aug. 26, 1943 

